: the top chamber, or atria, first, followed by the bottom. In A-Fib, the top chamber beats erratically, or fibrillates. This can be caused by a myriad of reasons, ranging from problems intrinsic to the heart (for example, valvular heart disease), to conditions apart from the heart (for example, chronic lung disease). A.Fib can even be caused by conditions outside the chest (for example, an overactive thyroid). In addition to trying to find the cause of the arrhythmia, the cardiologist must address the consequences.
Many patients are completely asymptomatic and the condition is diagnosed when the patient’s pulse is noted to be irregular on exam or electrocardiogram. Other patients note a pounding in their chest, since atrial fibrillation, when untreated, presents with a rapid and irregular heart beat. As a result, the patient may feel dizzy, or light-headed, short of breath, or even chest discomfort, since the heart’s beating is out of sync (think of pistons firing out of sync, resulting in an engine not working efficiently). When the heart is not pumping efficiently because its components are contracting out of synch, fluid can back up, instead of being pumped forward.
While the appropriate testing is conducted to search for the cause, therapy is initiated. If the cause can be ameliorated, for example, an abnormality in blood chemistries, that is promptly addressed. If the patient is found to have a rapid heart rate, medications are given to control it. At the same time, treatment of the consequences, if present, is started. Additionally, from the time of diagnosis, the most important consequence of the arrhythmia is addressed.
The hallmark for this condition is the irregular pulse. Mechanically, the irregular heart beat results in the top chamber, or atrium, not fully emptying each time it contracts. This results in blood staying behind in the fibrillating chamber. Blood, normally in constant motion as it circulates though the body, has the ability to pool in the atrium, and form clots in the irregularly contracting heart chamber. These clots may stay in that chamber, where they cause no damage, or break off, and travel into the circulation. It most commonly migrates to the brain, where it can cause an embolic stroke. In fact, one of the most common causes of stroke is underlying atrial fibrillation. Certain conditions increase the risk of stroke. They include a history of congestive heart failure, elevated blood pressure, age greater than 75, diabetes and previous stroke.
Clots can be prevented from forming by treatment with blood thinners. Currently, the only approved oral medication is Coumadin, also known at wafarin. This medication works by inhibiting the body’s normal clotting mechanism. This medication is difficult to regulate. It interacts with many other prescribed drugs, as well as over the counter medications and even certain foods. In addition, it can make it difficult to control any bleeding that occurs. The level therefore requires frequent monitoring and often adjusting: too little is less than effective, too much puts the individual at risk for excessive bleeding. Patients on this medication must be vigilant at the start of any bleeding. Sometimes, wounding and thus bleeding is inevitable, for example in surgery. When this is planned, for example for elective dental procedures, the medication is held for the several days before the procedure.
There are approaches to dealing with the arrhythmia directly. These include medications, but even well intentioned medications can have untoward side effects, including causing even more dangerous arrhythmias. Finally, cardiologists may perform a so called catheter ablation: the physician advances a catheter to the site where the arrhythmia is originating, and destroys a small amount of tissue to correct the problem.
And so, though A-Fib is rarely lethal, its consequences are prevented with appropriate treatment on careful monitoring. And that is no lie.
Dr. Marc Singer practices cardiology and internal medicine in Lake Success and is on staff at both Long Island Jewish Medical Center and North Shore Hospital, Manhasset.
